"The Hawaiian Islands lie above a geological “hot spot” in the earth’s mantle that has been volcanically active for the past 70 million years, with the island of Hawaii (the “Big Island”) having the most recent activity. The Big Island has an obvious, large potential for geothermal energy resources, both for electrical generation and direct utilization. Since the 1976 drilling of the HGP-A well and the discovery of the Kapoho Geothermal Reservoir in the lower Kilauea East Rift Zone, geothermal power potential on the Big Island has been estimated at between 500 and 700 Megawatts."pp. 11 to 21 in the Geo-Heat Center Bulletin.